1. Field of the Invention
This invention relates to an improved message access arrangement for a radio telecommunications system such as Universal Mobile Telecommunications System (UMTS) and relates especially to the selection of preamble signatures.
2. Description of the Related Art
During the set up of a call from a mobile telephone to the UMTS system, a mobile needs to select a preamble signature from the available signatures; subsequently, while waiting for an acquisition indication, the mobile may reselect a signature. It may occur that the mobile selects a signature associated with a stalled state, or that collisions occur, and call connection is delayed.
In WO98/18280 Ericsson, there is disclosure of a mobile telecommunication system in which each mobile requesting access can transmit one of a number of different preamble bit or signal patterns, referred to as “signatures”, stored in an internal memory location. The mobile selects one of the stored signatures randomly. However, the arrangement does not address the issue of avoiding stalled states or collisions.